Carburetors



May 25, 1965 L. MENNESSON CARBURETORS 2 Sheets-Sheet 1- Filed July 2.1962 ATTORNEYS May 25, 1965 A. L. MENNESSON CARBURETORS Filed July 2,I962 2 Sheets-Sheet 2 l N VE N TOR A/m r: law} Mwm/crrm 22 B y UnitedStates Patent O 3,185,453 CAR- BURETORS Andr Louis Mennesson,Neuilly-sur-Seine, France, assignor to Societe Industrielle de Brevetset dEtudes S.I.B.E., Neuilly-sur-Seine, France, a a

, society of France Filed July 2, 1962, Ser. No. 206,582 Claimspriority, application g rance, July 17, 1961,

68,1 3 Claims. (c1. 261-39) carburetors further comprising a cam forcontrolling the idling running position of the throttle valve andcapable of holding said throttle valve slightly open when the chokevalve is at least partly closed.

The object of the present invention is to provide a carburetor of thiskind capable of quickly reducing the minimum degree of opening of thethrottle valve immediately after the engine has been started.

For this purpose, a carburetor according to my invention ischaracterized in that the above mentioned throttle valve is controlledby said thermostatic device for values of the engine temperaturewithirra range above a given limit value and by a second thermostaticdevice, also responsive to variations of the engine temperature, forvalues of said temperature within a second range of temperatures lowerthan the first one, thewhole being arranged in such manner that thesecond thermostatic device is placed out of connection with the cam assoon as the engine is started with an engine temperature below saidlimit value. p

A preferred embodiment of this invention will be hereinafter describedwith reference to the appended drawings, given merely by way of example,and in which:

FIG. 1 is a diagrammatic vertical section of a carburetor according tothe invention, the elements of this carburetor being shown in theposition they occupy when the engine is at rest and its temperature isequal to the limit between the two above mentioned temperature ranges;

FIG. 2 is a horizontal section on the line IIII of FIG. 1;

FIG. 3 is a viewsimilar to FIG. 1, the elements being shown in theposition they occupy when the engine is at rest and its temperature iswithin the lower temperature range;

FIG. 4 is a view similar to FIGS. 1 and 3 showing the elements in theposition they occupy when the engine has just been started.

The carburetor comprises an induction pipe 1 provided with an air intake2. A system for the introduction of the primary mixture of air and fuelinto induction pipe 1 has not been shown on the drawing for the sake ofsimplicity, this system being for instance of any known type.

A choke valve 3 is mounted in the air intake 2 upstream of said system,this valve 3 being pivoted eccentrically about an axis 4 (in the drawingthe direction of flow of the gases is indicated by the arrow visible inFIG. 1). Choke valve 3 is urged in the opening direction by the airstream sucked into the carburetor, but its opening is limited by theaction of a first thermostatic device 5 (visible in FIG. 2) which closessaid choke valve 3 when the engine temperature is equal to or lower than(i.e., at

most equal to) a given temperature limit.

on a rotating spindle 7 located downstream of said system forintroducing the primary mixture. This throttle valve 6 is actuatedthrough the usual control means (not 1 shown) such that when saidcontrol means are released,

the throttle valve is resiliently returned to its minimum openingposition. This minimum opening position is determinedby a cam 8, whichis the fast idle cam. For this purpose, as shown, this cam acts, throughteps 8a carried by it, upon an abutment 1t (preferably adjustable, asshown) carried by a lever 11 fixed on the spindle 7 of throttle valve 6.

Choke valve 3 is connected to thermostatic device 5 through transmissionmeans comprising a lever 13 fixed on the spindle 4 of valve 3, aconnecting rod 14-, a lever 15 and a spindle 16 on which are fixed thislever 15 and another lever 17. Thermostatic device 5 consists of aspiral wound bimetallic strip. An arm 17a of lever 17 is engaged in thehook-shaped end of strip 5, the inner end of said strip being secured ina fixed axis 18. This strip I 15 is kept in position by a disc 19.

According to the present invention cam 8 is controlled by said firstthermostratic device 5 within a first range of temperature (for instanceabove +20 C.) and by a second thermostatic device 9, also responsive tovariations of the engine temperature, within a second range oftemperature lower than the first one (in the present case below +20 C.)and the whole is arranged in such 7 manner that the second thermostaticdevice is placed out of connection with cam 8 as soon as the engine hasstarted with an engine temperature within the second temperature range.

For this purpose, in the embodiment of the invention illustrated by thedrawings, earn 8 i rotatable in both directions about its axis but isconstantly urged in the direction tending to reduce the minimum openingof throttle valve 6 (in the clockwise direction in FIGS. 13 and 4) andthe rotation of cam 8 in this direction is limited by two abutments 17dand 9a, controlled respectively by said thermostatic devices 5 and 9,said devices being adjusted in such manner that both of these abutmentsare in contact with cam 8 when the engine temperature is equal to thelimit between the two temperature ranges (+20" 0), abutment 9a beingsubjected to the action of pneumatic means capable of placing it out ofconnection with cam 8 (by pushing it in the clockwise direction) whenthe engine, started at a temperature within the lower temperature range,produces a sufficient suction downstream of throttle valve 6.

In order to have cam 8 urged to rotate in the clockwise direction, thiscam is mounted on a fixed sleeve 20 coaxial with spindle 16 in suchmanner that said cam can rotate in both directions, but the center ofgravity of cam 8 is located above the horizontal plane passing throughspindle 16 and always on the right hand side of the vertical planepassing through this spindle, so that the weight of this cam tendsconstantly to rotate it in the clockwise direction.

The abutment controlled by thermostatic device 5 to limit this rotationconsists of a bent portion 17d of lever 17 cooperating with a projection8b of cam 8, thermostatic device 5 being arranged to rotate lever 17 inthe clockwise direction when the temperature rises.

The second thermostatic device 9 consists of a spiral wound bimetallicstrip mounted about sleeve 20, the inner end of this strip 9 being fixedto this sleeve 20 and the outer end of said strip being bent in a radialdirection so as to form the abutment 9a against which bears a pin 21rigid with cam 8. Thermostatic device 9 is adjusted in such manner thatits end 9a moves in the clockwise direction when the temperature rises.

The above mentioned pneumatic means consist of a piston 24 slidable in acylinder 25 so as to define therewith a variable volume chamber fromwhich starts a conduit 26. This conduit 26 opens, at 27, into pipe 1downstream of throttle valve 6. Piston 24 is connected through a rod 28to one end 17b of lever 17, near which is located the above mentionedbent portion 17a. In order to move the end 9a of thermostatic device 9out of connection with cam 8, lever 17 carries an arm 17c intended topush said end 9a in the clockwise direction when piston 24 is suckedupwardly.

Both of the thermostatic devices 5 and 9 are placed in a common casing12 heated through any suitable means when the engine is started.

Preferably, as shown, said casing 12 is located close to throttle valve6 so that spindle 7 can penetrate directly into said casing and lever 11can be fixed on the end of this spindle.

In order to permit initial adjustment of bimetallic strip 5, the wallsof casing 12 comprise a fixed portion 22 through which passes spindle16, and a cover 23 carrying spindle 18, this cover being adjustableangularly with respect to fixed portion 22.

In order to heat the inside of casing 12, hot air is circulatedtherethrough. This air comes from a tube 29 passing close to the exhaustpipe 30 of the engine, this hot air being circulated owing to the factthat the inside of casing 12 is in communication with a portion ofinduction pipe 1 located downstream of throttle valve 6. For instance,piston 24 is provided with a hole placing the inside of casing 12 incommunication with conduit 26.

The means for heating casing 12 might consist of an electrical resistor,located in said casing, arranged to be fed with current when the engineis started. Said means might also consist of a circulation of hot liquidin the wall of cover 23.

Fixed portion 22 and cover 23 are preferably made of a heat insulatingmaterial such as a plastic material, strip 5 being provided with ascreen 31 to limit its heatmg.

This carburetor works as follows:

If the engine temperature is the limit between the two above mentionedtemperature ranges, for instance +20 C., the elements occupy, before theengine is started, the positions of FIG. 1, after a partial opening ofthrottle valve 6 intended to release its steps 8a from contact withscrew 10. Choke valve 3 is closed. Throttle valve 6 is in a positionmore opened than the position for idling when the engine is warm andthis position of throttle valve 6 is determined by the contact of theprojection 8b of cam 8 with the bent portion 17d of lever 17 and at thesame time by the contact of pin 21 carried by cam 8 with the bent end 9aof thermostatic device 9.

Thermostatic devices 5 and 9 are made in such manner that if the enginetemperature passes from the above mentioned limit value (+20 C.) to ahigher value, abutment 17d, controlled by thermostatic device 5, movesin the clockwise direction a distance smaller than the displacement ofthe abutment 9a of thermostatic device 9. Therefore, in this case, theposition of cam 8 is determined by thermostatic device 5, by contact ofabutment 17d with the projection 8b of the cam.

If the engine temperature is within the lower temperature range, beingfor instance equal to 0 C. or even 20 C., thermostatic devices 5 and 9might both tend to displace their respective abutments 17d and 9a in theanti-clockwise direction. But this movement is impossible for abutment17d, because the lever 17 which carries it, is connected throughtransmission means 13, 14, 15 with choke valve 3 which is then Whollyclosed and consequently prevented from turning in the directioncorresponding to a rotation of lever 17 in the anticlockwise direction.On the contrary the abutment 9a of thermostatic device 9 is free to movein the anti-clockwise direction to come into the position of FIG. 3,thus pushing cam 8 in this direction by acting upon the projecting pin21 thereof. As a consequence the degree of opening of this valve 6 isincreased.

Therefore in all cases, when the engine is started, throttle valve 6 isset in an idling running position which depends upon the enginetemperature which itself is determined by the atmospheric temperature.

As soon as the engine is started, piston 24 is lifted and choke valve 3begins to open. Piston 24 causes lever 17 to pivot in the clockwisedirection and abutment 17c pushes the end 9a of thermostatic device 9away from pin 21 (FIG. 4). If the driver does not move the throttlepedal, throttle valve 6 remains locked in the position it occupiedprecedingly (determined by cam 8 in the position thereof correspondingto the solid lines position of abutment 10). But if the driver depressessaid pedal he releases cam 8, which then pivots in the clockwisedirection under the effect of its weight to come into the position shownin dotted lines. In this position, pin 21 carried by earn 8 is incontact with the end 9a of thermostatic device 9 precedingly pushed byabutment 17c (or alternately the projection 81) of cam 8 has come intocontact with the bent portion 17d of lever 17). Throttle valve 6 thenoccupies an idling running position which is more closed thanprecedingly so that the speed of the engine is lower.

As thermostatic device 5 is heated more and more, piston 24 moves uptoward its end position, while choke valve 3 moves toward its fullyopened position.

The end 9a of thermostatic device 9 follows this movement, either due toits own heating or because it is pushed by arm 170, which permits agradual rotation of cam 8 in the clockwise direction if it is releasedby intermittently displacing the pedal.

As soon as piston 24 has reached the end of its movement, the positionof cam 3 corresponds to the normal idling running position of theengine.

Of course the above described embodiment of the invention is givenmerely by way of example.

What I claim is:

1. In a carburetor for an internal combustion engine, the combination ofan induction pipe with an air intake, an unbalanced choke valve in saidpipe mounted to be urged in the opening direction by the inflow of airthrough said pipe, a first thermostatic device responsive to enginetemperature variations, transmission means mounted between said firstthermostatic device and said choke valve for closing said valve forengine temperatures up to a given limit and allowing it to open more andmore as the engine temperature is higher and higher above said limit, athrottle valve in said pipe downstream of said choke valve, a cammounted rotatable in both directions with respect to said pipe, said cambeing operatively connected with said throttle valve for determining theidling running position thereof, means for urging said cam constantly torotate in the direction corresponding to decreasing openings of saidthrottle valve, a second thermostatic device responsive to enginetemperature variations, said transmission means between said firstthermostatic device and said choke valve including an abutment adaptedto cooperate with said cam for rotating it in a direction opposed tosaid last mentioned direction when the engine temperature is less andless above said limit temperature, means operatively connected with saidsecond thermostatic device and forming an abutment for said cam torotate it in the direction corresponding to increasing openings of saidthrottle valve when the engine temperature is more and more below saidlimit temperature, pneumatic means operative by the suction created insaid pipe downstream of said throttle valve when the engine is startedfor imparting to said transmission means a displacement opening saidchoke valve, and an abutment carried by said transmission means andadapted to cooperate with said second thermostatic device when it is ina position corresponding to an engine temperature below said limittemperature for placing said second thermostatic device out ofconnection with said cam in response to said displacement imparted tosaid transmission means.

2. A combination according to claim 1 wherein said cam is constantlyurged in the direction corresponding to decreasing openings of saidthrottle valve by the action 7 of gravity upon said cam.

3. A combination according to claim ,1 further comprising a casingcontaining both of said thermostatic devices and means for circulatingthrough said casing a fluid at a temperature varying with the enginetemperature.

References Cited by the Examiner UNITED STATES PATENTS 2,262,408 11/41Read 261-69 5 2,394,665 2/46 Christian 26139 2,939,445 6/60 Sterner26139 2,943,848 7/60 Gordon et al 261-39 HARRY B. THORNTON, PrimaryExaminer.

10 HERBERT L. MARTIN, Examiner.

1. IN A CARBURETOR FOR AN INTERNAL COMBUSTION ENGINE, THE COMBINATION OFAN INDUCTION PIPE WITH AN AIR INTAKE, AN UNBALANCED CHOKE VALVE IN SAIDPIPE MOUNTED TO BE URGED IN THE OPENING DIRECTION BY THE INFLOW OF AIRTHROUGH SAID PIPE, A FIRST THERMOSTATIC DEVICE RESPONSIVE TO ENGINETEMPERATURE VARIATIONS, TRANSMISSION MEANS MOUNTED BETWEEN SAID FIRSTTHERMOSTATIC DEVICE AND SAID CHOKE VALVE FOR CLOSING SAID VALVE FORENGINE TEMPERATURES UP TO A GIVEN LIMIT AND ALLOWING IT TO OPEN MORE ANDMORE AS THE ENGINE TEMPERATURE IS HIGHER AND HIGHER ABOVE SAID LIMIT, ATHROTTLE VALVE IN SAID PIPE DOWNSTREAM OF SAID CHOKE VALVE, A CAMMOUNTED ROTATABLE IN BOTH DIRECTIONS WITH RESPECT TO SAID PIPE, SAID CAMBEING OPERATIVELY CONNECTED WITH SAID THROTTLE VALVE FOR DETERMINING THEIDLING RUNNING POSITION THEREOF, MEANS FOR URGING SAID CAM CONSTANTLY TOROTATE IN THE DIRECTION CORRESPONDING TO DECREASING OPENINGS OF SAIDTHROTTLE VALVE, A SECOND THERMOSTATIC DEVICE RESPONSIVE TO ENGINETEMPERATURE VARIATIONS, SAID TRANSMISSION MEANS BETWEEN SAID FIRSTTHERMOSTATIC DEVICE AND SAID CHOKE VALVE INCLUDING AN ABUTMENT ADAPTEDTO COOPERATE WITH SAID CAM FOR ROTATING IT IN A DIRECTION OPPOSED TOSAID LAST MENTIONED DIRECTION WHEN THE ENGINE TEMPERATURE IS LESS ANDLESS ABOVE SAID LIMIT TEMPERATURE, MEANS OPERATIVELY CONNECTED WITH SAIDSECOND THERMOSTATIC DEVICE AND FORMING AN ABUTMENT FOR SAID CAM TOROTATE IT IN THE DIRECTION CORRESPONDING TO INCREASING OPENINGS OF SAIDTHROTTLE VALVE WHEN THE ENGINE TEMPERATURE IS MORE AND MORE BELOW SAIDLIMIT TEMPERATURE, PNEUMATIC MEANS OPERATIVE BY THE SUCTION CREATED INSAID PIPE DOWNSTREAM OF SAID THROTTLE VALVE WHEN THE ENGINE IS STARTEDFOR IMPARTING TO SAID TRANSMISSION MEANS IS DISPLACEMENT OPENING SAIDCHOKE VALVE, AND AN ABUTMENT CARRIED BY SAID TRANSMISSION MEANS ANDADAPTED TO COOPERATE WITH SAID SECOND THERMOSTATIC DEVICE WHEN IT IS INA POSITION CORRESPONDING TO AN ENGINE TEMPERATURE BELOW SAID LIMITTEMPERATURE FOR PLACING SAID SECOND THERMOSTATIC DEVICE OUT OFCONNECTION WITH SAID CAM IN RESPONSE TO SAID DISPLACEMENT IMPARTMENT TOSAID TRANSMISSION MEANS.